1. Field of the Invention
The invention relates to a self-opening and re-sealable pouring element of plastics material for application to a pack for liquids, and in particular a composite card/plastics material pack, having a base part which has an attaching flange, having a cutting element and having a screw cap, the cutting element being rotatably arranged in the interior of the base part and being operatively connected to the screw cap in such a way that, when the screw cap is unscrewed for the first time, an opening for pouring is produced by the cutting element in the material of the pack.
2. Description of the Related Art
Self-opening and re-sealable pouring elements of the kind specified above are known in practice in a wide variety of versions. The pouring elements which are proving more and more popular in this case are ones which have a screw cap which, when unscrewed for the first time, causes a cutting element, by means of members providing positive guidance, to make a pouring opening in the composite material which was previously entirely tightly sealed. The known pouring element of the generic kind is therefore in three parts: a base part, a cutting element and a screw cap.
Known from U.S. Pat. No. 5,482,176 is a pouring element in three parts in the case of which all three of the parts have to be produced separately and then assembled to one another. To do this, the cutting element is screwed into the base part and in a second step the screw cap is thumped onto the base part. Assembly of this kind is relatively costly and complicated.
To simplify the assembly of known pouring elements of this kind, it has already been proposed (EP 1 088 764 B1) that the base part be injection moulded in one piece with the cutting element, this being accomplished by arranging the cutting element, by means of connecting bridges, in a spaced-away position below the floor of the base part which has the attaching flange. For the two parts to be assembled to one another, the only other thing which has to be done is for them to be screwed into one another.
In the case of another known pouring element (EP 0 385 603 A1), the base part and cutting element are likewise produced in one piece as an preformed assembly, but the connecting bridges which connect the two parts together are not broken until the time of first opening by the consumer.
Taking the above as a point of departure, the object underlying the invention is to design and refine the three-piece pouring element which was specified in the opening paragraph and has been described above in such a way that particularly simple and hence inexpensive production becomes possible. Easy assembly is also desired.